Sorry for the bad summary, I tried but couldn't come up with a better one. I just updated my project (using Subclipse), and Spring IDE shows lots of errors in my applicationContext.xml file, related to classes that do not exist. These classes were deleted by a teammate, and their references removed from Spring's config. If the Spring Builder ran when it should, these errors wouldn't show up. Editing applicationContext.xml, eg. adding a space, "forces" the Spring Builder to run and this makes these errors go away.